The headlamps of most modern motor vehicles comprise a reflective housing closed by a transparent lens, a replaceable bulb inserted within a removable socket adjacent the rear surface of the reflective housing, and one or more vents which allow communication between the air within the enclosed headlamp and the atmosphere surrounding same.
When the bulb is switched off, the air within the headlamp cools and contracts, causing atmospheric air to be drawn into the interior of the headlamp through the vent. Any moisture and dust contained in the inflowing air can accumulate within the headlamp. Water may condense on the reflective surfaces and the lens of the headlamp, which may interfere with the reflection and transmission of light. Moreover, dust may settle on the reflective surfaces and the lens causing reduced illumination from the headlamp. Depending upon the configuration of the vent, water splashed onto the exterior surfaces of the headlamp during normal operation of the vehicle in wet weather may also enter the headlamp, further diminishing the illumination provided by the headlamp.
U.S. Pat. No. 5,207,497 discloses a vehicle light fixture venting construction, comprising a rubber pipe having integrally molded inner baffles. The rubber pipe is attached to a portion of the light fixture having a baffling chamber. This combination is said to reduce the inspiration of dust into the light fixture. The required inner baffles for the rubber pipe and baffling chamber within the light fixture increase the complexity and cost of manufacture for the vent and light fixture.
U.S. Pat. No. 4,405,974 discloses a filter system for a lamp, comprising a filter assembly threadably fastenable to the lamp, said filter assembly containing a filter medium. Wire screens on both major surfaces of the filter medium secure the medium into a fitting of the assembly. The wire screens may corrode due to the moisture in the air passing into and out of the lamp through the filter assembly, thus blinding off the filter medium or allowing it to fall out of the fitting.
It would be desirable to have a ventilation system for a motor vehicle light fixture which would resist the accumulation dust within the fixture while allowing the elimination of moisture from therein, and which could be simply and inexpensively manufactured and installed.